Science Objectives

Intact polar diacyglycerols (IP-DAGs) are the fatty-acid bearing lipid molecules that compose bacterial and eukaryotic cell membranes. As such, they are one of the most abundant classes of lipid molecules in plankton, and play a major role in the marine carbon cycle. However, until very recently, the molecular diversity of IP-DAGs was poorly understood; the structural identity and characteristics of IP-DAGs were inferred almost exclusively from their constituent fatty acids. Led by advances in high performance liquid chromatography/mass spectrometry (HPLC/MS) methods, we have established that the IP-DAGs in the upper ocean are dominated by sulfolipids and betaine lipids. These non-phosphorus containing IP-DAGs were largely unknown to chemical oceanography. In contrast, phospholipids, which have been the focus of considerable research, compose a disproportionally small fraction of total IP-DAGs. Over the last three years we have made some progress in understanding the planktonic origins of non-phosphorus IP-DAGs and have identified the possibility that sulfolipids and betaine lipids are substituted for phospholipids by phytoplankton when dissolved phosphate becomes scarce. But we still lack even a cursory understanding of biochemical functions and geochemical fates of non-phosphorus IP-DAGs. Given that these molecules are among the most abundant lipid molecules on the planet, this represents a profound and unexpected gap in our understanding the marine carbon and phosphorus cycles. In this proposal we outline a research plan to begin to rectify this situation. Specifically, we will ask:

• How do non-phosphorus lipids contribute to variations in the C:N:P of particulate organic matter in the Sargasso Sea?

• What are the relative degradation rates of phospholipids and non-phosphorus lipids in surface waters?

• Which groups of microbes utilize the carbon and phosphorus from different IP-DAGs?

• What are the relative contributions of different IP-DAGs to particulate organic matter export to the deep-sea?

Science Activities

We plan to conduct two, 5-day quasi-lagrangian time-series stations at 65W, one north the Gulf Stream and one south of the Gulf Stream. The daily cruise track will be centered around following our free-floating sediment net traps arrays. We will retrieve and re-deploy traps on 24 hour intervals (generally beginning at day break). In the afternoons, we will conduct CTD casts, primarily in the upper 250 m. Overnight, we will deploy McLane pumps.

Additional Info

Pre-cruise Planning Meeting: Visit WHOI

Meeting Notes: I'm around most of the rest of December, and am now able to focus on preparing for this cruise.

Navigation

Navigation

Navigation Notes:
WE will be chasing drifting traps, and will rely on Argos for that.

Winches

CTD Winch with .322" Electro-mechanical wire

Hydro Winch with .25" hydro wire

Other Portable Winch

Winch Notes:
We will need two small deck mounted winches for use during net trap recovery and deployment.

Wire use and application

CTD Winch with .322" Electro-mechanical wire

Hydro Winch with .25" hydro wire

Other

Wire Notes:
We will use the CTD winch for the Knorr's CTD. The hydro wire is need to deploy McLane pumps; there will be up to six of these and they weigh approx 80lbs in air and 60 lbs in water. The two small deck mounted winches will be used for net trap recovery and deployment. The net traps are very lightweight, about 100 lbs each in air, and 80 lbs in water. Including flotation, line and ballast, the whole rig is well under 500 lbs. We need two winches because it makes is much easier to cycle multiple floating net trap rigs.

Standard Oceanographic Cables

Slip ring required? no

Number of conductors:

Non-standard wire required? no

Type:

Traction winch required? no

Describe:

Portable Vans

Chemical Storage Van

Isotope Van

Specialized Deck Equipment

Mooring Deployment/Recovery Equipment Required: no

Type:

Cruise Specific Science Winch Required: yes

Type: Light winch, described above

Nets Required: no

Type:

Over the Side Equipment

Will you be bringing any equipment (winches, blocks, etc.) that lowers instruments over the side?

no

Special Requirements

Elecrical Power: no

Identify:

Equipment Handling: no

Identify:

Inter/intraship Communications: no

Identify:

Science Stowage: yes

Identify: Everything we have will need to be on the Knorr cruise led by Bidle, which is June 15 to 14 July

Water: yes

Identify: We will need the ship's flow-through system. Also, LOTS of DI water.

Additional Cruise Items/Activities

Explosive Devices:

no

Portable Air Compressors:

no

Flammable Gases:

no

Small Boat Operations:

no

SCUBA Diving Operations:

no

Hazardous Material

Will hazardous material be utilized?

yes

Describe deployment method and quantity:

Radioactive Material

Radioiosotopes:

yes

Additional Information

Is night time work anticipated on this cruise?

yes

Specialized tech support (Seabeam, coring, other):

Other required equipment and special needs:We will needs lots of fume hood space. I'm not sure where or how big the Knorr's fume hood is, but we might want to think about making an additional fume hood (this will be needed on the Bidle cruise too).